Field of the Invention
The present invention relates to self-expanding intravascular devices for implantation within the vessel of a body. In particular, the present invention relates to an improved distal capture device for use with a self-expanding stent in the treatment of blood vessel disorders.
Description of Related Art
Expandable stents, i.e., expandable tubular skeletal structures, are commonly used today for such treatments as reinforcing diseased blood vessels, opening occluded blood vessels or relieving pressure in aneurysms. Stents that are expandable may be classified as either “balloon expandable” or “self-expanding.” Balloon-expandable stents expand upon the inflation of the balloon, whereas self-expanding stents automatically expand upon removal of a force that otherwise retains the stent in an elastically compressed state. Different types of self-expanding stents have been developed, for example, a laser cut stent or a braided stent. A catheter-based delivery system is used to position the expandable stent at a desired location within a blood vessel. Many systems are available for delivering the stent to the desired location. Several exemplary delivery system configurations are disclosed in U.S. Pat. Nos. 7,309,351; 7,201,769; 7,037,331; 7,001,422; 6,960,228; 6,960,227; 6,955,685; 6,833,003; 6,818,013; 6,673,106; 6,612,012, all of which are co-owned by the same assignee of the present invention and each is hereby incorporated by reference in its entirety.
Axial traversal of the stent within the blood vessel occurs using a delivery catheter having a lumen defined axially therethrough for receiving the stent while in a compressed/unexpanded state having a reduced diameter. The catheter is sufficiently flexible, yet rigid, so that it may be pushed distally as it transverses through a blood vessel. While in a compressed state, the stent is introduced into the lumen via the proximal end of the delivery catheter. Conventional self-expanding stents may have a pushing surface to aid in advancing the stent distally through the catheter. Upon emerging out from the distal end of the delivery catheter, the stent automatically deploys to an expanded state in physical contact with the interior surface of the blood vessel.
The distal or leading edge of the expandable stent presses outward against the inner surface of the delivery catheter as it traverses therethrough. Due to its small size and delicate construction, it is desirable to minimize delivery forces required for the stent to transverse axially through the lumen of the catheter. When traversing axially, the distal or leading edge of a self-expanding stent may undesirably radially flare open thereby requiring significant supplemental delivery force to push past any obstacle (e.g., features, edges or imperfections) encountered along the way within the lumen of the delivery catheter. It would therefore be desirable to develop an improved delivery system for a self-expanding stent that eliminates or minimizes supplemental delivery forces required to push the distal leading edge of the stent past any obstacle disposed along the lumen of the delivery catheter.